An open-label, phase II study published in the British Journal of Haematology found that, in patients with chronic lymphocytic leukemia (CLL) who achieved negative minimal residual disease (MRD) status with chemotherapy, consolidation therapy with alemtuzumab improved progression-free survival (PFS) and overall survival (OS). The results confirm remission duration and survival in patients with CLL are dependent on the level of MRD after treatment, wrote the authors, led by Abraham M. Varghese, MRCP, from the Department of Hematology at the Leeds Teaching Hospitals National Health Services Trust in the United Kingdom.

Dr. Varghese and authors used multi-parameter flow cytometry to screen patients’ blood samples for MRD six to 24 months after induction chemotherapy. Patients who were MRD-positive (n=47) then received alemtuzumab 30 mg, administered subcutaneously three times per week for six weeks. If patients reached MRD-negativity or were non-responsive at this point, therapy was discontinued; MRD-positive patients received an additional six weeks of immunotherapy consolidation.

In the study, 47 patients received consolidation with alemtuzumab. After consolidation, 83 percent of patients (n=39) achieved MRD-negative status, with 38 percent (n=18) remaining MRD-negative six months later. Among these 18 patients, the median time to MRD relapse was 46 months, “which was similar to patients who were MRD-negative at baseline,” the authors noted.

The five-year PFS and OS were significantly higher for those who were MRD-negative at six months, compared with MRD-positive patients (78% vs. 39% [p=0.010] and 89% vs. 64% [p=0.029], respectively).

Thirty-six percent of patients (n=17) experienced a total of 22 serious adverse events (AEs); 19 of these were deemed treatment-related. One death related to alemtuzumab was reported.